JP2020060249A - Shaft sealing device and shaft sealing system - Google Patents

Abstract

To satisfy a requirement that measures for a problem of the leakage of powder in a transport pipe to the outside from a clearance between a rotating drive shaft and the transport pipe, and a problem of the intrusion of contaminations into the transport pipe are required.SOLUTION: This shaft sealing device for sealing a clearance between a transport pipe and a rotating drive shaft of transport means comprises a cylindrical housing which is constituted so as to allow the insertion of the rotating drive shaft. A gas supply port for supplying a gas into the housing is formed at the housing. On the inside of the housing, a spiral groove spiraling in an opposite direction to a rotation direction of the rotating drive shaft when viewed from the shaft sealing device toward the transport pipe is formed toward an end part of the transport pipe side from the gas supply port, and a spiral groove spiraling to a forward direction or an opposite direction with respect to the rotation direction is formed toward the gas supply port from an end part at a side opposite to the transport pipe.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a shaft sealing device that seals between a transport pipe and a rotary drive shaft of a transport means inserted into the transport pipe from an end wall of the transport pipe for transporting powder in the transport pipe, and Regarding shaft seal system.

  BACKGROUND ART Conventionally, there is known a technique of rotating a rotating member provided inside a container to stir the powder and a seal for preventing the powder from leaking between a rotary drive shaft that rotates the rotating member. Has been.

  Patent Document 1 discloses a shaft sealing device that seals between a powder processing container having a stirring means inside and a rotary drive shaft inserted from an end wall of the container for driving the stirring means. , A housing that has an air chamber inside, and is hermetically disposed on the outer wall surface of the container end wall with the rotary drive shaft inserted in the air chamber, and an air chamber with a pressure higher than the internal pressure of the container. The pressurized air supply source that supplies pressurized air and the container end wall surface side in the air chamber are arranged coaxially in a non-contact manner with the rotary drive shaft, and the pressurized air can pass between the rotary drive shaft and the rotary drive shaft. Disclosed is a shaft sealing device having a cylindrical seal collar that forms a fine seal gap.

  In Patent Document 2, a kneading rotor is rotatably fitted in a housing provided with a powdery and granular material supply port in an upward opening shape, and a shaft seal housing is externally fitted to a drive shaft portion of the rotor. A fixing ring is fixed to the fixing ring and an air supply annular space is formed, and the gas supplied to the annular space passes through a gas conduction gap between the drive shaft portion and the fixing ring to pass from the gap between the housing and the kneading rotor to the inside of the housing. In a shaft sealing device for a kneading machine rotor, which is designed to be discharged into a shaft, a peripheral groove is formed in a shaft sealing housing at a position closer to a shaft end than a gas supply passage in the annular space, and a drive shaft is formed in the peripheral groove. Disclosed is a shaft sealing device for a kneading machine rotor, in which a disc provided in the section is loosely fitted and a viscoelastic body such as grease is filled.

JP, 2007-239933, A Japanese Patent Laid-Open No. 06-055052

  It is required to deal with the problem that the powder in the transportation pipe leaks out through the gap between the rotary drive shaft of the transportation means and the transportation pipe, and the problem of contamination entering from the outside air into the transportation pipe.

  Therefore, the present invention provides a shaft seal for sealing between a transport pipe and a rotary drive shaft of a transport means for transporting powder in the transport pipe, which is inserted into the transport pipe from an end wall of the transport pipe. An object is to provide a device and a shaft sealing system.

The present invention includes the following embodiments.
[1]
A shaft sealing device which seals between a transport pipe and a rotary drive shaft of a transport means for transporting powder in the transport pipe, which is inserted into the transport pipe from an end wall of the transport pipe,
A cylindrical housing configured such that the rotary drive shaft is inserted therethrough,
The housing is configured such that when the rotary drive shaft is inserted into the housing, a gap is formed between the rotary drive shaft and an inner surface of the housing.
A gas supply port for supplying gas into the housing is formed in the housing,
On the inner surface of the housing, there is provided a spiral groove that is opposite to the rotation direction of the rotary drive shaft when viewed from the shaft sealing device toward the transport pipe, and has an end portion on the transport pipe side from the gas supply port. And a spiral groove that is forward or counterclockwise with respect to the rotation direction is formed from the end opposite to the transport pipe toward the gas supply port.
The shaft sealing device according to the above.
[2]
The shaft sealing device according to [1], wherein the gap from the gas supply port to the end on the transport pipe side is larger than the gap from the gas supply port to the end on the side opposite to the transport pipe.
[3]
The gas supply port is formed at a position of 30 to 70%, 40 to 60%, or 45 to 55% of the axial length of the housing from the end on the transport pipe side, [1]. Alternatively, the shaft sealing device according to [2].
[4]
The shaft sealing device according to any one of [1] to [3], further including a cover configured to cover the housing.
[5]
The shaft sealing device according to any one of [1] to [4], wherein the powder is a powder of polycarbonate.
[6]
A transport means for transporting the powder in the transport pipe, and a shaft sealing device for sealing between the transport pipe and a rotary drive shaft of the transport means inserted into the transport pipe from an end wall of the transport pipe. A shaft sealing system having
The shaft sealing device includes a cylindrical housing configured so that the rotary drive shaft is inserted therethrough,
The housing is configured such that when the rotary drive shaft is inserted into the housing, a gap is formed between the rotary drive shaft and an inner surface of the housing.
A gas supply port for supplying gas into the housing is formed in the housing,
On the surface of the rotary drive shaft, a spiral groove that is opposite to the rotation direction of the rotary drive shaft when viewed from the shaft sealing device toward the transport pipe has a spiral groove corresponding to the gas supply port. A spiral groove that is formed from a position on the surface of the shaft toward a position on the surface of the rotary drive shaft that corresponds to the end on the side of the transport pipe, and that is forward or reverse to the rotation direction is the transport groove. It is formed from a position on the surface of the rotary drive shaft corresponding to the end opposite to the tube to a position on the surface of the rotary drive shaft corresponding to the gas supply port.
The shaft sealing system according to the above.

  In the shaft sealing device according to the embodiment of the present invention, “the inner surface of the housing has a spiral groove in a direction opposite to a rotation direction of the rotary drive shaft when viewed from the shaft sealing device toward the transport pipe. Is formed from the gas supply port toward the end on the side of the transport pipe, and a spiral groove that is forward or reverse to the rotation direction is formed from the end opposite to the transport pipe to the gas supply port. The gas supplied from the gap gas supply port between the housing of the shaft sealing device and the rotary drive shaft is configured so that the gas is supplied to the housing of the shaft sealing device and the rotary drive shaft. The powder in the transport pipe is prevented from leaking out of the transport pipe by receiving a synergistic effect of the labyrinth effect and the effect of improving the gas flow velocity while passing through the gap between The same applies to the following. It can be. In addition, since the gas also flows from the gas supply port to the atmosphere side through the gap, the invasion of air from the atmosphere is prevented (including reduction to a desired amount of invasion with no influence. The same applies hereinafter. ), And it is possible to prevent the invasion of contamination.

It is a schematic diagram of the powder transportation system provided with the shaft sealing device which concerns on one Embodiment. It is a perspective view of a shaft seal device concerning one embodiment. It is a sectional view of a shaft seal device concerning one embodiment. It is a perspective view of a shaft seal device concerning one embodiment. It is sectional drawing of the shaft sealing system which concerns on other embodiment.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a schematic diagram of a powder transportation system 1 including shaft sealing devices 10a and 10b (collectively referred to as “shaft sealing device 10”) according to an embodiment of the present invention.

  The powder transport system 1 includes a transport pipe 3, a screw conveyor-shaped transport means 20 provided inside the transport pipe 3, and transporting the powder by rotating from the upstream end wall 3a side to the downstream end wall 3b side. A drive device 5 for rotationally driving the rotary drive shaft 25 (outer diameter d) of the transportation means 20, a shaft support structure 6 rotatably supporting the rotary drive shaft 25 on the opposite side of the drive device 5, and a transport pipe 3. The shaft sealing devices 10a and 10b that seal the gap between the shaft and the rotary drive shaft 25 are provided.

  The rotary drive shaft 25 of the transport means 20 is inserted through the sealing devices 10a and 10b and the transport pipe 3, and is rotatably supported by the drive device 5 and the shaft support structure 6 provided on the opposite side thereof. It is rotated by the driving force of. The drive device 5 includes a motor (not shown) and a mechanism for transmitting the driving force to the rotary drive shaft 25.

  The shaft seal device 10a is attached to the upstream end wall 3a of the transport pipe 3 by a fixture (not shown), and prevents the powder from leaking out from the gap between the upstream end wall 3a and the rotary drive shaft 25. The invasion of air and contamination from the atmosphere into the transportation pipe 3 is also prevented. Similarly, in the shaft sealing device 10b, the powder leaks from the gap between the downstream end wall 3b and the rotary drive shaft 25, which is attached to the downstream end wall 3b of the transport pipe 3 by a fixture (not shown). And the invasion of air and contamination from the atmosphere into the transport pipe 3 is also prevented.

  In the powder transport system 1, the powder loaded into the transport pipe 3 from the loading pipe is transported from the upstream end wall 3a side of the transport pipe 3 to the downstream end wall 3b side by the rotation of the transport means 20, and It is sent to another process through a rotary valve.

  The powder is a powder of a synthetic resin, for example, a polycarbonate resin, a polyamide resin, a polyacetal resin, a polybutylene terephthalate resin, a polyethylene terephthalate resin, a fluororesin, an acrylic resin, a styrene resin, or a powder of a combination thereof. Although not limited thereto, as one application example of the powder transportation system 1, powder of a polycarbonate resin in a wet state is charged into the transportation pipe 3 from a charging pipe, and the inside of the transportation pipe 3 from the upstream end 3a. A case may be considered in which it is transported toward the downstream end 3b and sent to a step of drying the powder through a rotary valve.

  FIG. 2 is a schematic perspective view of the shaft sealing device 10 (10a, 10b). The shaft seal device 10 includes a cylindrical housing 11 configured so that the rotary drive shaft 25 is inserted therethrough. One or a plurality of gas supply ports 12 for supplying gas into the housing 11 are formed at predetermined positions in the direction along the central axis of the housing 11 (axial direction). A spiral groove 13 is formed on the inner surface of the housing 11.

  As shown in FIG. 2, the length of the housing 11 in the axial direction is L. The gas supply port 12 is formed at a position having a length L1 from one end 11a of the housing 11 and a length L2 from the other end 11b in the axial direction of the housing 11 (L = L1 + L2). . A plurality of gas supply ports 12 are formed in the circumferential direction of the housing 11 at that position, one at a time or at predetermined intervals.

  The range of L1 (or L2) is usually 0.3L ≦ L1 (or L2) ≦ 0.7L, preferably 0.4L ≦ L1 (or L2) ≦ 0.6L, and more preferably 0. .45L ≦ L1 (or L2) ≦ 0.55L. L1 = L2 may be sufficient.

  The gas supply port 12 is connected to a gas supply source (not shown), and the gas supplied from the gas supply source is introduced into the housing 11 via the gas supply port 12. The gas is a gas such as air, nitrogen, carbon dioxide, or argon, but since it enters the transportation pipe 3, a gas that does not chemically react with the powder is preferable.

  Assuming the shaft sealing device 10a, the end 11b of the housing 11 of the shaft sealing device 10a is attached so as to contact the upstream end wall 3a of the transport pipe 3 (see FIG. 3 (a)). In the inner surface of the housing 11 of the shaft sealing device 10a, in the axial direction of the housing 11, (i) from the gas supply port 12 toward the end 11b on the transport pipe 3 side, from the shaft sealing device 10a toward the transport pipe 3. The spiral groove 13 is formed in the direction opposite to the rotation direction of the rotary drive shaft 25 when viewed, and (ii) from the other end 11a toward the gas supply port 12, the rotation direction is normal or opposite to the rotation direction. Spiral groove 13 is formed.

  That is, in the inner surface of the housing 11, in the axial direction of the housing 11, with the gas supply port 12 as a boundary, (i) the region on the side of the transport pipe 3 when viewed from the shaft sealing device 10a toward the transport pipe 3. The spiral groove 13 is formed in the opposite direction to the rotation direction of the rotary drive shaft 25, and (ii) the spiral groove 13 is formed in the region opposite to the transport pipe 3 in the normal or opposite direction to the rotation direction. Has been done. In addition, the spiral groove 13 on the side opposite to the transportation pipe 3 of (ii) is preferably formed in the normal direction, so that the effect of preventing the invasion of outside air can be further expected.

  The spiral groove 13 may be formed by cutting the groove in a spiral shape on the inner surface of the housing 11, or may be formed by providing a protrusion in a spiral shape on the inner surface of the housing 11.

  The inner diameter D of the housing 11 is larger than the outer diameter d of the rotary drive shaft 25 (D> d), and the rotary drive shaft 25 and the central axis of the housing 11 coincide with each other. Is inserted into the housing 11, a gap is formed between the rotary drive shaft 25 and the inner surface of the housing 11. The gap may be designed in consideration of the effect of shaft runout of the rotary drive shaft 25 and the labyrinth effect (sealing effect) of the spiral groove 13. For example, when there is an influence of shaft runout (for example, several mm) of the rotary drive shaft 25, the gap may be designed in advance to be several times (for example, 2 to 3 times) the runout width.

  In order to enhance the labyrinth effect, the gap between the inner surface of the housing 11 in which the spiral groove 13 is formed and the rotary drive shaft 25 is made small, and the pitch of the spiral groove 13 is increased (the distance between adjacent grooves). It is conceivable to increase the length of the flow path through which the gas passes (by decreasing). Further, the spiral groove 13 extends from the gas supply port 12 toward the end 11b on the side of the transport pipe 3 in a direction opposite to the rotation direction of the rotary drive shaft 25 when viewed from the shaft sealing device 10 side toward the transport pipe 3. By forming, the flow velocity of the gas flowing through the flow path of the spiral groove 13 can be improved as compared with the case of forming in the normal direction.

  That is, in the shaft sealing device 10 of the present embodiment, the labyrinth effect of the spiral groove 13 and the spiral groove 13 is formed in the region (i) on the side of the transport pipe 3 in the direction opposite to the rotation direction of the rotary drive shaft 25. Due to the synergistic effect with the improvement of the flow velocity of the gas, it is possible to more effectively prevent the powder from leaking from the transport pipe 3 as compared with the conventional technique.

  In addition, in the shaft sealing device 10 of the present embodiment, the formation direction of the spiral groove 13 in the region on the side opposite to the transportation pipe 3 of (ii) is not limited to the direction opposite to the rotation direction of the rotary drive shaft 25. However, the spiral groove extends from the end 11a toward the gas supply port 12 in a direction that is the same as the rotational direction of the rotary drive shaft 25 when viewed from the drive device 5 (or shaft support structure 6) side toward the transport pipe 3. By forming 13, the flow velocity of gas is improved and the invasion of air from the outside air can be prevented more effectively, similar to the effect of the spiral groove 13 in the region on the side of the transport pipe 3 in (i) above. it can.

  Regarding the inner diameter of the housing 11, the inner diameter of the region (i) on the side of the transport pipe 3 and the inner diameter of the region (ii) on the side opposite to the transport pipe 3 may be different (D1 in FIG. 3). , D2). That is, in the axial direction of the housing 11, (i) the inner diameter from the gas supply port 12 to the end 11b on the transport pipe 3 side is D2, and (ii) the end on the opposite side from the gas supply port 12 to the transport pipe 3. If the inner diameter up to 11a is D1, D1> D2 or D1 <D2 may be satisfied. Note that D1 = D2 may be satisfied.

  Assuming that the relationship between the inner diameters D1 and D2 of the housing is D2> D1, the amount of gas supplied through the gas supply port 12 is larger than that of the above (i) as compared with the amount flowing in the region opposite to the transport pipe 3 (i). It is possible to relatively increase the amount of flow in the region on the side of the transportation pipe 3 of (4). Further, the influence of the shaft runout being relatively large due to the distance from the drive device 5 or the shaft support structure 6 can be avoided. Of course, the labyrinth effect can be expected to be smaller as the gap becomes smaller. However, the inner diameter of the housing 11 may be designed in consideration of the influence of shaft runout and the gas flow rate due to the large gap.

  For example, as will be described later, in a case where the problem of air invasion can be reduced by a cover that covers the outside of the housing 11, invasion of air can be prevented, so that the gas flowing from the gas supply port 12 is transferred to the transport pipe 3 of (i) above. It is advisable to increase the gap (D2> D1) so that a large amount of gas flows in the side region.

  3A and 3B are schematic cross-sectional views through the central axes of the shaft sealing devices 10a and 10b attached to the upstream end wall 3a and the downstream end wall 3b of the transport pipe 3 by a fixture, respectively.

  In the configuration shown in FIG. 3, the inner diameter of the housing 11 from the gas supply port 12 to the end portion 11b of each of the shaft sealing devices 10a and 10b is taken into consideration in consideration of the influence of the shaft runout of the rotary drive shaft 25 and the increase of the gas flow rate. D2 (and the gap s2 between the rotary drive shaft 25) is larger than the inner diameter D1 of the housing 11 from the gas supply port 12 to the other end 11a (and the gap s1 between the rotary drive shaft 25). Is configured as follows. If there is no influence of the shaft runout of the rotary drive shaft 25, the gap s2 may be the same as the gap s1, or the gap s2 may be smaller than the gap s1 in order to obtain a more labyrinth effect.

  FIG. 4 is a schematic perspective view of a configuration including a cover 30 attached so as to cover the shaft sealing device 10a. The whole or a part of the cover 30 is formed of a transparent member so that the shaft sealing device 10a inside can be seen. The material of the cover 30 may be formed of polycarbonate, for example. By providing the cover 30 so as to cover the shaft sealing device 10a, it is possible to prevent air from entering the transport pipe 3 from the atmosphere and accompanying contamination. Although not shown, similarly, the cover 30 may be attached so as to cover the shaft sealing device 10b.

  Next, FIG. 5 is a cross-sectional view of a shaft sealing system 100 according to another embodiment of the present invention. In the present embodiment, the spiral groove 13 is not formed on the inner surfaces of the shaft sealing devices 10a and 10b, but the spiral groove 130 is formed on the surface of the rotary drive shaft 250 of the transportation means 20. Is different from. The spiral groove 130 may be formed by spirally cutting the surface of the rotary drive shaft 250, or may be formed by providing a spiral projection on the surface of the rotary drive shaft 250. .

  On the surface of the rotary drive shaft 250 that passes through the inside of the shaft seal device 10a, in the axial direction of the rotary drive shaft 250, (a) the rotary drive shaft 250 corresponding to the gas supply port 12 of the housing 11 of the shaft seal device 10a. When viewed from the shaft sealing device 10a toward the transport pipe 3 from the position 120 on the surface toward the position 110b on the surface of the rotary drive shaft 250 corresponding to the end 11b on the transport pipe 3 side of the housing 11. The spiral groove 130 is formed in the opposite direction to the rotation direction of the rotary drive shaft 250. In addition, on the surface of the rotary drive shaft 250 that is inserted through the inside of the shaft sealing device 10a, in the axial direction of the rotary drive shaft 250, (b) the rotary drive corresponding to the end portion 11a of the housing 11 opposite to the transport pipe 3 is formed. From the position 110a on the surface of the shaft 250 toward the position 120 on the surface of the rotary drive shaft 250, which corresponds to the gas supply port 12 of the housing 11 of the shaft sealing device 10a, looking from the shaft sealing device 10a toward the transport pipe 3. The spiral groove 130 is formed in the normal direction or the opposite direction to the rotation direction of the rotary drive shaft 250 at that time.

  The shaft sealing system 100 of this embodiment has the same effects as the above embodiments. That is, the labyrinth effect of the spiral groove 130 and the improvement of the gas flow rate due to the spiral groove 130 formed in the area (a) on the side of the transport pipe 3 in the direction opposite to the rotation direction of the rotary drive shaft 250 are synergistic. Due to the effect, it is possible to more effectively prevent the powder from leaking out from the transport pipe 3 as compared with the related art. Since the other points are the same as those in the above-described embodiment, the description thereof will be omitted.

  The dimensions, materials, shapes, relative positions of components, etc. described in the above embodiments are arbitrary, and are changed according to the structure of the device to which the present invention is applied or various conditions. Further, the present invention is not limited to the specifically described embodiments.

1 Powder Transport System 3 Transport Pipe 5 Drive Device 6 Shaft Support Structure 10 Shaft Sealing Device 11 Housing 12 Gas Supply Ports 13, 130 Spiral Groove 20 Transport Means 25, 250 Rotation Drive Shaft 30 Cover 100 Shaft Sealing System

Claims (6)

A shaft sealing device which seals between a transport pipe and a rotary drive shaft of a transport means for transporting powder in the transport pipe, which is inserted into the transport pipe from an end wall of the transport pipe,
A cylindrical housing configured such that the rotary drive shaft is inserted therethrough,
The housing is configured such that when the rotary drive shaft is inserted into the housing, a gap is formed between the rotary drive shaft and an inner surface of the housing.
A gas supply port for supplying gas into the housing is formed in the housing,
On the inner surface of the housing, there is provided a spiral groove that is opposite to the rotation direction of the rotary drive shaft when viewed from the shaft sealing device toward the transport pipe, and has an end portion on the transport pipe side from the gas supply port. And a spiral groove that is forward or counterclockwise with respect to the rotation direction is formed from the end opposite to the transport pipe toward the gas supply port.
The shaft sealing device according to the above.   The shaft sealing device according to claim 1, wherein the gap from the gas supply port to the end on the transport pipe side is larger than the gap from the gas supply port to the end on the opposite side to the transport pipe.   The gas supply port is formed at a position 30 to 70%, 40 to 60%, or 45 to 55% of the axial length of the housing from the end on the transport pipe side. Or the shaft sealing device according to 2.   The shaft sealing device according to claim 1, further comprising a cover configured to cover the housing.   The shaft sealing device according to claim 1, wherein the powder is a powder of polycarbonate. A transport means for transporting the powder in the transport pipe, and a shaft sealing device for sealing between the transport pipe and a rotary drive shaft of the transport means inserted into the transport pipe from an end wall of the transport pipe. A shaft sealing system having
The shaft sealing device includes a cylindrical housing configured so that the rotary drive shaft is inserted therethrough,
The housing is configured such that when the rotary drive shaft is inserted into the housing, a gap is formed between the rotary drive shaft and an inner surface of the housing.
A gas supply port for supplying gas into the housing is formed in the housing,
On the surface of the rotary drive shaft, a spiral groove that is opposite to the rotation direction of the rotary drive shaft when viewed from the shaft sealing device toward the transport pipe has a spiral groove corresponding to the gas supply port. A spiral groove that is formed from a position on the surface of the shaft toward a position on the surface of the rotary drive shaft that corresponds to the end on the side of the transport pipe, and that is forward or reverse to the rotation direction is the transport groove. It is formed from a position on the surface of the rotary drive shaft corresponding to the end opposite to the tube to a position on the surface of the rotary drive shaft corresponding to the gas supply port.
The shaft sealing system according to the above.